Finding and Eliminating Rattles in your Home Theater (or your car)

Finding and Eliminating Rattles in your Home Theater (or your car)

Last night, Nicole and I had several friends over and we wound up watching The Sentinel. The movie was not all that great but what I found even more distracting was the rattles in the room generated by the substantial bass of my subwoofer. I was probably the only one in the room that noticed or was disturbed by it, but so what. So today I’m identifying the offenders in the room.

I know the door covering the equipment rack is rattling and there is a light fixture in the ceiling rattling as well. But both rattle at different frequencies and it’s a pain to re-watch movies trying to find the sections that caused the brief rattles. So I use a tone generator to generate different frequencies and isolate and troubleshoot the offending rattlers at each frequency. To do this, you need a Windows or Mac PC, a Palm PDA, or a Windows Mobile PDA and the NCH Tone Generator for the appropriated Operating System.

Attach your PC / PDA to your receiver using an RCA adapter cable (or your car stereo using a cassette tape adapter) and start a sine wave test tone at 100 Hz and work down to 15 Hz. You’ll easily be able to figure out which frequencies cause which rattles.

Fixing the problem is the difficult part. Dynamat is a great product for eliminating rattles. Generous amounts of duct tape or extra screws are other alternatives. Using a rubber or foam window seal/door stripping are other alternatives. Be creative. Basically, you want to increase the natural frequency by making the rattling part more stiff or by adding more mass to it. Be patient and keep trying and your rattles can be eliminated!

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Update: The rattles turned out to be from a lose vent in the ceiling, the bottom edge of the equipment rack where it touches the surrounding frame, and the wood frame around the subwoofer. The last the number one offender. Covering all of the wooden frame with felt should fix the problem. For now, I’ve just pushed-back the subwoofer so it doesn’t touch the frame (but it is now no longer flush with the wall opening).